aThe College of Physicians and Surgeons of Ontario only provided a list of physicians who consented to release their information for research purposes (~60%). In 2012, there were an estimated 26 382 physicians in Ontario (Source: https://www.ophrdc.org/Public/Report.aspx.)bOntarians were selected from the Registered Persons Database.cUnable to link to other databases because of missing/invalid names and physician numbers. List of physicians was linked to the Institute for Clinical Evaluative Sciences physician database based on unique physician number and the Registered Persons Database based on first name, last name, and date of birth (90% linked).dWe set this exclusion criteria because we only wanted individuals who visited a physician or interacted with the provincial health care at least once in the prior 5 years to ensure they remained Ontario citizens. The results did not appreciably change when we excluded this criterion.eSimilar strategy used to match registered physicians to registered citizens to compare those who opted to exclude certain organs or tissues from donation (specifically kidneys, heart, eyes, bone, liver, lungs, skin, and pancreas). We matched 6122 registered physicians to 24 488 registered matched citizens (93% matched).

A shortage of organs for transplant has prompted many countries to encourage citizens to register (“opt in”) to donate their organs and tissues when they die.1 However, less than 40% of the public is registered for organ donation in most countries with a registry.1 One common fear is that physicians will not take all measures to save the life of a registered citizen at a time of illness.2 Showing that many physicians are registered for organ donation themselves could help dispel this myth. Although most physicians in surveys support organ donation,3 whether they are actually registered remains unknown.

Methods

We conducted a population-based cross-sectional study using linked health care databases from Ontario, Canada, as of May 17, 2013. We obtained a list of active physicians from the College of Physicians and Surgeons of Ontario (approximately 60% consented to release information for research).4 This list was linked to the Institute for Clinical Evaluative Sciences physician database based on unique physician number and the Registered Persons Database based on first name, last name, and date of birth (90% linked). From these 2 databases, we obtained demographic information and donor registration status. The data were complete with the exception of 4 variables, which each had less than 2% missing data. As of 2008, Ontario’s organ and tissue donor registry recorded only yes responses. Citizens at least 16 years of age are able to register online or by mail. Citizens are also prompted to consider registration when renewing their driver license or health card. Those who register can opt to exclude certain organs or tissues from donation (eg, cornea, heart).

A comparison group of Ontario citizens with similar sociodemographic backgrounds as the physicians were selected from the Registered Persons Database, matched (4:1) to each physician on age, sex, income, and residential neighborhood (99% matched). We compared the proportion of physicians registered for organ donation with the general public or matched citizens (χ2 or McNemar test, respectively; 2-tailed P < .05 interpreted as significant). We used multivariable log-binomial regression to estimate the prevalence ratio and 95% confidence interval of various physician factors associated with donor registration (SAS version 9.3; SAS Institute Inc).5 The research ethics boards at Sunnybrook Health Sciences Center and Western University approved the study and waived informed consent.

Among physicians, factors significantly associated with higher donor registration were younger age, sex (women), living in a rural community, physician specialty (emergency medicine, internal medicine, pediatrics, or psychiatry vs family medicine) and graduating from a Canadian (vs foreign) medical school (Table).

Discussion

To our knowledge, this is the first study to document rates of actual organ donor registration among physicians, rather than expressed support for donation. Physicians were more likely to register than the general public. Similar to factors associated with registration in nonphysicians,6 younger physicians and women were more likely to register. However, half of all physicians were not registered.

One study limitation is that we had data on the majority of, but not all, physicians in the province. We also had no information on the reasons why some physicians were yet to register, which would be useful to address potential barriers. Future research should determine if our findings are generalizable to other countries.

Conflict of Interest Disclosures: The authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Ms Prakash is the Vice President of Operations at Ontario’s organ procurement organization, Trillium Gift of Life Network. Dr Kim reported receiving investigator-initiated research grants from Astellas Canada, Novartis Canada, and Genzyme Canada. Dr Knoll reported receiving investigator-initiated research grants from Astellas Canada and Wyeth/Pfizer Canada. Dr Garg reported receiving an investigator-initiated grant from Astellas and Roche to support a Canadian Institutes of Health Research study in living kidney donors. No other disclosures were reported.

Funding/Support: This Institute for Clinical Evaluative Sciences (ICES) project was conducted by the provincial Kidney, Dialysis, and Transplantation program. ICES is funded by an annual grant from the Ontario Ministry of Health and Long-term Care, and the Kidney, Dialysis, and Transplantation program is funded by an operating grant from the Canadian Institutes of Health Research. Core funding for ICES Western is provided by the Academic Medical Organization of Southwestern Ontario, the Schulich School of Medicine and Dentistry, Western University, and the Lawson Health Research Institute. Mr Li is supported by an Allied Health Doctoral Fellowship from the Kidney Foundation of Canada. Dr Lam is supported by a KRESCENT postdoctoral fellowship award and the Clinical Investigator Program at Western University.

Role of the Sponsor: The sponsors had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Disclaimer: The opinions, results, and conclusions are those of the authors and are independent from the funding sources. No endorsement by these organizations is intended or should be inferred.

Additional Contributions: We thank Nelson Chong, BSc, and Charlotte Ma, BEng, for linking the datasets; Karey Iron, MHSc, for helping obtain organ and tissue donor registration data; and Craig Nathanson, PhD, for helping obtain data from the College of Physicians and Surgeons of Ontario. None received compensation for their role in the study.